ABSTRACT
In the U.S., melons are widely available year round and represent an important
dietary component. In 2001 annual per capita consumption was estimated to be
14.9, 11.2, and 2.1 pounds for watermelon, cantaloupe, and honeydew melons
respectively [1]. The value of these commodities in 2003 was reported to be
$346,022,000, $372,965,000, and $93,241,000, respectively [2]. In recent years
fresh-cut melons have become increasingly popular with consumers and now
account for a large and growing proportion of melon consumption. For most consumers, melons represent a refreshing and healthy dessert
or snack. However, for a small number of consumers, the situation is quite
different; melon consumption has been a source of foodborne illness. At least
17 melon-related outbreaks involving hundreds of cases have been reported
since 1990 [3-5]. Additional outbreaks ascribed to ‘‘multiple fruit’’ or ‘‘fresh-
cut fruit’’ also may have been due to contamination of an unspecified melon
component. While the largest melon-related outbreaks have been attributed to
various salmonella serotypes, other human pathogens including Escherichia
coli O157:H7, Campylobacter jejuni, and Norwalk-like virus also have been
implicated [4]. Survival and growth of human pathogens including salmonella, E. coli
O157:H7, and Listeria monocytogenes in melon flesh has been demonstrated
[6-8]. Annous et al. [9] reported growth of S. Poona on cantaloupe rind at 20C. Salmonella outbreaks in 2000-2002 were traced by the U.S. Food and
Drug Administration (FDA) to melons imported from Mexico [10]. On-farm
investigations in Mexico conducted by the FDA concluded that ‘‘measures
were not in place to minimize microbial contamination in growing, harvesting,
packaging, and cooling of cantaloupe.’’ Detection of L. monocytogenes in cut
melons resulted in a recent product recall [11]. FDA surveys of imported and
domestic produce have documented the presence of salmonella and shigella in
cantaloupe [12,13]. The incidence of salmonella on imported cantaloupe (from
Mexico, Costa Rica, and Guatemala) was 5.3% and on domestic cantaloupes
was 2.6%. Shigella also was detected on these samples, an incidence of 2% on
the imports and 0.9% on domestic melons. On October 28, 2002 the FDA
issued an import alert on cantaloupes from Mexico, halting all such shipments.
Subsequently, export of Mexican cantaloupes to the U.S. by a small number of
grower/packers who met FDA safety criteria was resumed [10]. In this chapter some of the production and postharvest handling conditions
that may contribute to microbial contamination of melons are examined.
Studies of the efficacy of conventional washing practices in reducing the micro-
bial load on melons are reviewed. Finally, current research results pointing to
means of improving the efficacy of melon disinfection are examined.
